This invention relates to compounds, to inks comprising these compounds, ink jet printer cartridges containing these inks and to their use in ink jet printing (xe2x80x9cIJPxe2x80x9d).
IJP is a non-impact printing technique in which droplets of ink are ejected through a fine nozzle onto a substrate without bringing the nozzle into contact with the substrate.
There are many demanding performance requirements for dyes and inks used in IJP. For example they desirably provide sharp, non-feathered images having good water-fastness, light-fastness and optical density. The inks are often required to dry quickly when applied to a substrate to prevent smudging, but they should not form a crust over the tip of an ink jet nozzle because this will stop the printer from working. The inks should also be stable to storage over time without decomposing or forming a precipitate which could block the fine nozzle.
According to the present invention there is provided a compound comprising a disazo chromophore and an optionally substituted heterocyclic group linked together through a xe2x80x94SO2NHxe2x80x94 group.
Preferably the nitrogen atom of the xe2x80x94SO2NHxe2x80x94 group is attached to the heterocyclic group by means of a single covalent bond. It is especially preferred that the compound is of Formula (1):
Axe2x80x94NHxe2x80x94SO2xe2x80x94Bxe2x80x94Nxe2x95x90xe2x80x94Dxe2x80x94Nxe2x95x90Nxe2x80x94Exe2x80x83xe2x80x83Formula (1)
wherein:
A is an optionally substituted heterocylic group;
B and D are each independently optionally substituted phenylene or naphthylene; and
E is optionally substituted naphthylene.
The optionally substituted heterocyclic group preferably comprises an optionally substituted 5- or 6-membered heterocyclic ring, optionally having a benzene ring fused thereon. Preferred heterocyclic rings comprise 2, 3, 4 or 5 carbon atoms and 1, 2 or 3 atoms selected from oxygen, nitrogen and sulphur.
Preferably the optionally substituted heterocyclic group is an optionally substituted diazine, thiazole, benzthiazole, benzdiazine, isoxazole, benzisoxazole, thiadiazole, oxadiazole, isothiazole, triazole, benzisothiazole, pyridiazine, triazine, oxazole, thiophene, benzoxazole, pyrimidine or pyridine, preferably attached to the xe2x80x94NHxe2x80x94SO2xe2x80x94 group through a carbon atom adjacent to an oxygen, sulphur or nitrogen atom (e.g. at the 2-position). Particularly preferred are optionally substituted 2-thiazole, 2-benzthiazole and 2-diazine groups.
Preferably B is optionally substituted phenylene, more preferably optionally substituted 1,4-phenylene.
Preferably D is an optionally substituted 1,4-phenylene group, more preferably a group of the formula: 
wherein each:
W independently is H, optionally substituted alkyl, optionally substituted alkoxy, polyalkylene oxide, nitro, cyano, sulpho, halo, ureido, SO2F, hydroxy, carboxy, ester, PO4H2, xe2x80x94NR1R2, xe2x80x94COR1, xe2x80x94CONR1R2 or xe2x80x94SO2NR1R2;
X independently is O, NH or S;
R1 and R2 are each independently H or alkyl, preferably H or C1-4-alkyl; and
R3 independently is H, optionally substituted alkyl or optionally substituted aryl.
Preferably each W independently is H, C1-4-alkyl or C1-4-alkoxy more preferably H, methyl, ethyl, methoxy or ethoxy, especially H. Preferably both groups represented by W are H and X is O.
Preferably each R3 independently is optionally substituted C1-4-alkyl or optionally substituted phenyl more preferably C1-4-alkyl or C1-4-alkyl-OH, phenyl or phenyl carrying one or two substituents selected from carboxy and sulpho.
Preferred optional substituents which may be present on the optionally substituted heterocyclic group, B, D or E are each independently selected from alkyl, more preferably C1-4-alkyl; alkoxy, more preferably C1-4-alkoxy; polyalkylene oxide; nitro; cyano; sulpho; halo, especially bromo, chloro or fluoro; ureido; SO2F; hydroxy; carboxy; ester, more preferablyxe2x80x94CO2(C1-4-alkyl); PO4H2 and xe2x80x94NR1R2, xe2x80x94COR1, xe2x80x94CONR1R2 and xe2x80x94SO2NR1R2 wherein R1 and R2 are each independently H or alkyl, preferably H or C1-4-alkyl.
When D is also optionally substituted naphthylene it preferably carries one or more (preferably 1 to 4) substituents selected from hydroxy, amino, sulpho and carboxy.
Preferably E is optionally substituted naphthylene, more preferably carrying one or more (preferably from 1 to 4) groups selected from hydroxy, amino, sulpho and carboxy. More preferably E is naphthylene carrying one hydroxy group, one amino group and 0, 1 or 2 sulpho groups. It is especially preferred that E is a 1-hydroxy-3-sulphonaphth-2-ylene group carrying an optionally substituted amino group at the 7-position; or a 1-hydroxy-5-sulphonaphth-2-ylene group carrying an optionally substituted amino group at the 8-position; or a 1-hydroxy-3,6-disulphonaphth-2-ylene group carrying an optionally substituted amino group at the 8-position or a 1-hydroxy-3,6-disulphonaphth-2-ylene group carrying an optionally substituted amino group at the 7-position.
Preferred optionally substituted amino groups are of the formula xe2x80x94NR4R5 where R4 and R5 are independently selected from H, optionally substituted alkyl and optionally substituted phenyl. Preferably R4 and R5 are both H.
The compounds described hereinbefore are preferably soluble in water. To achieve this solubility, the compounds preferably have 1, 2 or 3 water-dispersing substituents. Preferred water-dispersing substituents are polyalkylene oxides and more preferably sulpho and carboxy.
Preferred polyalkylene oxide groups which may be present on A, B, D and/or E are poly(C2-3-alkylene oxide) groups, more preferably polyethylene glycol or polypropylene glycol, preferably having from 1 to 20 glycol units and terminated with a hydroxy or C1-4-alkoxy group.
Preferably A, B, D and E are selected from the definitions given above such that the pKa of the linking xe2x80x94NHxe2x80x94 group is from 8 to 3, more preferably 7.5 to 4, especially 7 to 4.5. These preferences arise from the finding that compounds having such an xe2x80x94NHxe2x80x94 group have a particularly good combination of water-fastness and optical density when printed on paper.
Any acid or basic groups on the compound, particularly carboxylic acid and sulphonic acid groups, are preferably in the form of a salt. Thus the Formulae shown herein include the compounds in free acid and in salt form.
The compounds of the invention may be prepared by condensing a diazo chromophore and an optionally substituted heterocyclic compound, where one has a sulphonyl halide substituent and the other has an amino substituent. This condensation is preferably performed in the present of base to absorb hydrogen halide as it is generated during the condensation.
The compound of Formula Axe2x80x94NHxe2x80x94SO2xe2x80x94Bxe2x80x94Nxe2x95x90Nxe2x80x94Dxe2x80x94Nxe2x95x90Nxe2x80x94E may be prepared by diazotising an amine of the formula Axe2x80x94NHxe2x80x94SO2xe2x80x94Bxe2x80x94Nxe2x95x90Nxe2x80x94Dxe2x80x94NH2 and coupling the resultant diazonium salt with a compound of the formula Hxe2x80x94E.
The compound of Formula Axe2x80x94NHxe2x80x94SO2xe2x80x94Bxe2x80x94Nxe2x95x90Nxe2x80x94Dxe2x80x94NH2 may be prepared by diazotising an amine of the formula Axe2x80x94NHxe2x80x94SO2xe2x80x94Bxe2x80x94NH2 and coupling the resultant diazonium salt with an amine of the formula Hxe2x80x94Dxe2x80x94NH2. In some cases it may be necessary for the amino group to carry a protecting group which should be removed on completion of the reaction.
Many compounds of the formula Axe2x80x94NHxe2x80x94SO2xe2x80x94Bxe2x80x94NH2 are commercially available.
Preferably they may be prepared by condensing an amine of formula Bxe2x80x94(NH2)2, in which one of the amino groups is protected, with a compound of formula Clxe2x80x94SO2xe2x80x94NHxe2x80x94A followed by removal of the protecting group.
More preferably they may be prepared by condensing an amine of formula Axe2x80x94NH2 with a compound of formula Clxe2x80x94SO2xe2x80x94Bxe2x80x94NH2 carrying a protecting group on the amino group. of the Clxe2x80x94SO2xe2x80x94Bxe2x80x94NH2 compound, followed by removal of the protecting group.
Diazotisation is preferably performed at a temperature below 6xc2x0 C., more preferably at a temperature in the range xe2x88x9210xc2x0 C. to 5xc2x0 C. Preferably diazotsation is performed in water. The coupling reactions are performed at a pH below 7 for the monoazo intermediate and above pH 7 to form compounds of Formula (1). Dilute mineral acid, e.g. HCl or H2SO4, may be used to achieve the desired acidic conditions.
In the above processes, A, B, D and E are as hereinbefore defined.
Preferred salts are alkali metal salts, especially lithium, sodium and potassium salts, ammonium and substituted ammonium salts. Especially preferred salts are salts with ammonia and volatile amines. The compounds may be converted into a salt using known techniques. For example, an alkali metal salt of a compound may be converted into a salt with ammonia or an amine by dissolving an alkali metal salt of the compound in water, acidifying with a mineral acid and adjusting the pH of the solution to pH 9 to 9.5 with ammonia or the amine and removing the alkali metal cations by dialysis or by treatment with an ion exchange resin.
The compounds described hereinbefore may exist in tautomeric forms other than those shown in this specification. These tautomers are included within the scope of the present claims. The compounds are particularly useful as dyes, especially for ink jet printing compositions.
According to a second aspect of the present invention there is provided a composition comprising a compound according to the first aspect of the invention, preferably of Formula (1), and a liquid medium.
Preferred compositions comprise:
(a) from 0.01 to 30 parts of a compound according to the first aspect of the invention, preferably of Formula (1); and
(b) from 70 to 99.99 parts of a liquid medium;
wherein all parts are by weight and the number of parts of (a)+(b)=100.
The number of parts of component (a) is preferably from 0.1 to 20, more preferably from 0.5 to 15, and especially from 1 to 5 parts. The number of parts of component (b) is preferably from 99.9 to 80, more preferably from 99.5 to 85, especially from 99 to 95 parts.
Preferably component (a) is completely dissolved in component (b). Preferably component (a) has a solubility in component (b) at 20xc2x0 C. of at least 10%. This allows the preparation of liquid dye concentrates which may be used to prepare more dilute inks and reduces the chance of the dye precipitating if evaporation of the liquid medium occurs during storage.
Preferred liquid media include water, a mixture of water and an organic solvent and an organic solvent free from water.
When the medium comprises a mixture of water and an organic solvent, the weight ratio of water to organic solvent is preferably from 99:1 to 1:99, more preferably from 99:1 to 50:50 and especially from 95:5 to 80:20.
It is preferred that the organic solvent present in the mixture of water and organic solvent is a water-miscible organic solvent or a mixture of such solvents. Preferred water-miscible organic solvents include C1-6-alkanols, preferably methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, tert-butanol, n-pentanol, cyclopentanol and cyclohexanol; linear amides, preferably dimethylformamide or dimethylacetamide; ketones and ketone-alcohols, preferably acetone, methyl ether ketone, cyclohexanone and diacetone alcohol; water-miscible ethers, preferably tetrahydrofuran and dioxane; diols, preferably diols having from 2 to 12 carbon atoms, for example pentane-1,5-diol, ethylene glycol, propylene glycol, butylene glycol, pentylene glycol, hexylene glycol and thiodiglycol and oligo- and poly-alkyleneglycols, preferably diethylene glycol, triethylene glycol, polyethylene glycol and polypropylene glycol; triols, preferably glycerol and 1,2,6-hexanetriol; mono-C1-4-alkyl ethers of diols, preferably mono-C1-4-alkyl ethers of diols having 2 to 12 carbon atoms, especially 2-methoxyethanol, 2-(2-methoxyethoxy)ethanol, 2-(2-ethoxyethoxy)-ethanol, 2-[2-(2-methoxyethoxy)ethoxy]ethanol, 2-[2-(2-ethoxyethoxy)-ethoxy]-ethanol and ethyleneglycol monoallylether; cyclic amides, preferably 2-pyrrolidone, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, caprolactam and 1,3-dimethylimidazolidone; cyclic esters, preferably caprolactone; sulphoxides, preferably dimethyl sulphoxide and sulpholane. Preferably the liquid medium comprises water and 2 or more, especially from 2 to 8, water-soluble organic solvents.
Especially preferred water-soluble organic solvents are cyclic amides, especially 2-pyrrolidone, N-methyl-pyrrolidone and N-ethyl-pyrrolidone; diols, especially 1,5-pentane diol, ethyleneglycol, thiodiglycol, diethyleneglycol and triethyleneglycol; and mono- C1-4-alkyl and C1-4-alkyl ethers of diols, more preferably mono- C1-4-alkyl ethers of diols having 2 to 12 carbon atoms, especially 2-methoxy-2-ethoxy-2-ethoxyethanol.
Although not usually necessary, further colorants may be added to the ink to modify the shade and performance properties. Examples of such colorants include C.I.Direct Yellow 86, 132, 142 and 173; C.I.Direct Blue 199, and 307; C.I.Food Black 2; C.I.Direct Black 168 and 195; C.I. Acid Yellow 23; and any of the dyes used in ink jet printers sold by Seiko Epson Corporation, Hewlett Packard Company, Canon Inc. and Lexmark International. Addition of such further dyes can increase overall solubility leading to less kogation (nozzle blockage) for the resultant ink.
Examples of further suitable liquid media comprising a mixture of water and one or more organic solvents are described in U.S. Pat. Nos. 4,963,189, 4,703,113, 4,626,284 and EP 4,251,50A.
When the liquid medium comprises an organic solvent free from water, (i.e. less than 1% water by weight) the solvent preferably has a boiling point of from 30xc2x0 to 200xc2x0 C., more preferably of from 40xc2x0 to 150xc2x0 C., especially from 50 to 125xc2x0 C. The organic solvent may be water-immiscible, water-miscible or a mixture of such solvents. Preferred water-miscible organic solvents are any of the hereinbefore described water-miscible organic solvents and mixtures thereof. Preferred water-immiscible solvents include, for example, aliphatic hydrocarbons; esters, preferably ethyl acetate; chlorinated hydrocarbons, preferably CH2Cl2; and ethers, preferably diethyl ether; and mixtures thereof.
When the liquid medium comprises a water-immiscible organic solvent, preferably a polar solvent is included because this enhances solubility of the compound in the liquid medium. Examples of polar solvents include C1-4-alcohols. In view of the foregoing preferences it is especially preferred that where the liquid medium is an organic solvent free from water it comprises a ketone (especially methyl ethyl ketone) and/or an alcohol (especially a C1-4-alkanol, more especially ethanol or propanol).
The organic solvent free from water may be a single organic solvent or a mixture of two or more organic solvents. It is preferred that when the medium is an organic solvent free from water it is a mixture of 2 to 5 different organic solvents. This allows a medium to be selected which gives good control over the drying characteristics and storage stability of the ink.
Liquid media comprising an organic solvent free from water are particularly useful where fast drying times are required and particularly when printing onto hydrophobic and non-absorbent substrates, for example plastics, metal and glass.
The liquid media may also contain additional components conventionally used in ink jet printing inks, for example viscosity and surface tension modifiers, corrosion inhibitors, biocides, kogation reducing additives and surfactants which may be ionic or non-ionic.
It is preferred that a composition according to the second aspect of the invention is an ink or liquid dye concentrate.
A third aspect of the invention provides a process for forming an image on a substrate comprising applying an ink according to the second aspect of the invention to the substrate by means of an ink jet printer.
The ink used in this process is preferably a composition as defined in the second aspect of the present invention.
The inks preferably have a total concentration of divalent metal ions and trivalent metal ions below 1000, more preferably below 100, especially below 20, more especially below 10 parts per million by weight relative to the total weight of ink. Pure inks of this type may be prepared by using high purity ingredients and/or by purifying the ink after it has been prepared. Suitable purification techniques are well known, e.g. ultrafiltration, reverse osmosis, ion exchange and combinations thereof.
The ink jet printer preferably applies the ink to the substrate in the form of droplets which are ejected through a small orifice onto the substrate. Preferred ink jet printers are piezoelectric ink jet printers and thermal ink jet printers. In thermal ink jet printers, programmed pulses of heat are applied to the ink in a reservoir by means of a resistor adjacent to the orifice, thereby causing the ink to be ejected in the form of small droplets directed towards the substrate during relative movement between the substrate and the orifice. In piezoelectric ink jet printers the oscillation of a small crystal causes ejection of the ink from the orifice.
The substrate is preferably paper, plastic, a textile, metal or glass, more preferably paper, an overhead projector slide or a textile material, especially paper.
Preferred papers are plain or treated papers which may have an acid, alkaline or neutral character.
A fourth aspect of the present invention provides a paper, an overhead projector slide or a textile material printed with an ink according to the second aspect of the invention, a compound according to the first aspect of the invention or by means of a process of the third aspect of the invention.
A fifth aspect of the present invention provides an ink jet printer cartridge comprising a chamber and an ink wherein the ink is in the chamber and the ink is according to the second aspect of the present invention.
A sixth aspect of the invention is a method for the colouration of a substrate which comprises treating with a compound according to f the first aspect of the invention.